Havana, Cuba — – When Laura Pollán's husband, a journalist, hosted his colleagues at their house in Havana, she busied herself in the kitchen making coffee. When their talk turned "too political," she left.

But since his imprisonment, the former high school teacher is now at the center of discussions, prayers, fasting – and a rare, impromptu street protest Monday. Ms. Pollán is a leader of the "Damas de Blanco" (Ladies in White), a group of wives, mothers, and sisters of 75 dissidents, many of them reporters, jailed after a sudden sweep of arrests nationwide in March 2003.

On Monday morning, Pollán and nine other Damas were roughed up by a mob and arrested near the offices of President Raúl Castro. "We are here to demand the release of our husbands and won't leave until they are free or they arrest us. We have waited long enough, we want to talk to the new president," Pollán said, according to Reuters.

Moments later, a bus pulled up and about 20 female corrections officers tried to arrest the women, who sat on the sidewalk, clasped arms, and refused to move. A mob of about 100 Cuban government supporters, mainly women from nearby government buildings, joined the fray, picking the Damas up, throwing them into the waiting bus, and yelling insults, Reuters reported.

Monday's protest was unusual. It may, as Pollán suggested in a recent interview here, reflect a broad, emerging expectation of loosening political restrictions in the one-party Socialist state.

Raúl Castro officially became Cuba's first new president in nearly 50 years in February, when he took over for his ailing brother Fidel Castro. Raúl has recently dropped restrictions on ownership of computers and cellphones, among other changes. Some here and abroad have expressed the hope he would go beyond granting access to consumer goods and services. But the government response to the Damas protest Monday may be designed to tamp down such expectations.

Certainly, the Damas have been the only tolerated expression of opposition for some time. Each Sunday, the Damas take to Havana's streets in a 10-block march that starts at Santa Rita de Casia Church and ends at a nearby park. Easily recognized by the all-white clothes they wear, the faces of their brothers and uncles worn as pins on their blouses, they seek the immediate release of their relatives, whom they say were given unfair trials and detained on false charges.

Observers say these women represent the only systematic, peaceful civil disobedience taking place today in Cuba. They have received global attention and won international accolades, and in doing so undergone a personal transformation that Pollán says she didn't know was within her.

"I started fighting for my husband, then for the group, and now it's for changes for the better of the country," says Pollán in an interview in her house. "We found qualities in ourselves we did not know we had."

The arrests of Pollán's husband, Héctor Maseda, along with 74 others, took place in a three-day period in 2003, known here as "Black Spring." Human rights activists say that their trials were cobbled together a few weeks later; Mr. Maseda only met his lawyer 15 minutes before the proceeding began. They were dubbed "mercenaries" of the US – because they published in foreign media outlets – and some were given sentences of nearly three decades.

Having nowhere else to turn, the Damas formed almost immediately, and since then they have never missed a Sunday march, including braving three cyclones. They have also been joined by Cubans who were not directly affected by "Black Spring." They have been compared to other women's groups like Argentina's "Mothers of the Plaza de Mayo," who protest for the children who were disappeared during that country's "dirty war."

The group always walks with gladioluses in their hands, wearing white to represent the innocence, they say, of their family members – and taking over streets that the government has always maintained belong to revolutionaries. But with their protests – including letters written to state officials and demands for airtime on state-owned television – many see them as today's revolutionaries, the ones trying to change the system. "Their courage is remarkable," says Carlos Serpa Maceira, an independent journalist in Havana, who has documented in photos the harassment of the group by those who consider them "counterrevolutionaries." Many Damas are heckled on the streets. Some have lost their jobs.

In 2005, the Damas won the European Union's Sakharov Prize for Freedom of Thought, among its most prestigious human rights awards. The New York-based Committee to Protect Journalists, upon the fifth anniversary of "Black Spring," recently called for the immediate release of the jailed journalists. They have helped garner condemnation around the world, including among left-leaning artists and writers and nations who typically defend Cuba.

"Black Spring" was not the first time Pollán's husband had gotten into trouble. He'd been detained for a day, sometimes two, once for a week. But when Pollán returned from work on March 19, 2003, she found 12 state agents standing in her ransacked home. Authorities confiscated two 1950s-era typewriters and news clippings in which Maseda had underlined comments made by public officials. Pollán says it was his effort to detect contradictions in the national polemic. He was given 20 years for threatening the "sovereignty" of the state.

Yet Hugo Landa, the director of CubaNet, a Miami-based outlet that receives reports from about 40 writers in Cuba, says that "Black Spring" has not curtailed journalism. In fact, Mr. Landa says, it has given more impetus to the trade. Many, like Mr. Serpa Maceira, wake up in the middle of the night, and without access to affordable Internet, they write their stories out longhand in notebooks and type them on computers at various embassies.

"They sent these independent journalists to jail to crush the independent press," says Landa. "But by doing that, they sent such a strong message of repression, that many more started to write."

But critics say they have little faith that real political change is under way, as long as freedom of expression is restrained.

On April 16, an article called "There will be no space for subversion in Cuba," appeared on the website of Cuba's state newspaper, Granma, and left no room for doubt about the government's view of political opposition. "There is no space," it reads, "for adversaries, fifth columnists, or internal mercenaries."

Jose Agramonte Leyva, a political dissident who spent three years in jail as part of the independent library movement, says that the Raúl Castro administration might have to find ways to justify imprisonment, but that those who wish to speak outside the government line will be just as much at risk and considered lackeys of the US – a label he disdains.

"I want to fight for justice here; until we have free elections we will have no liberty," he says. "All I want is to sit at my table and eat a piece of meat peacefully."

In the past five years, 20 of the 75 dissidents have been released from jail. Pollán, who sometimes has 25 women sleeping in her home, says that even though her husband remains in jail, she is hopeful.

On their fifth anniversary, when they marched for five consecutive days, they handed out popcorn in bags with the number "55" written on them – for those who are still behind bars. Not all accepted the gifts, but most did – a move that might be meaningless in a more open society but is telling in Cuba, she says.

"The more time passes, the worse it will be for the government," she says, pointing to a tiny statue of Santa Rita on her bookshelf. She's the saint of the "impossible," she says. "There is, every day, more solidarity. One way or another, it is a slow awakening."